FIG. 1 shows a schematic diagram illustrating the structure of a general color cathode ray tube. As shown in FIG. 1, the color cathode ray tube generally includes a glass envelope having a shape of bulb and being comprised of a faceplate panel 2 to which explosion prevention means is fixed, a tubular neck, and a funnel 3 connecting the panel 2 and the neck. A phosphor screen 7 is formed on the inner surface of the faceplate panel 2. The phosphor screen 7 is coated by phosphor materials of R, G, and B.
A multi-apertured color selection electrode, i.e., shadow mask 8 is mounted to the panel 2. The shadow mask 8 is hold by a peripheral frame 9. An electron gun 6 is mounted within the neck to generate and direct electron beams 5 along paths through the mask to the panel 2.
The cathode ray tube further comprises an inner shield 12 for shielding the tube from external geomagnetism. The inner shield 12 is joined to the frame 9. Further, a spring 10 for combining the frame 9 and the funnel 3 is joined to the frame 9.
The operation of the general cathode ray tube will be described shortly referring to FIG. 1.
The electron beams 5, which are radiated from the electron gun 6 by the voltage applied to the cathode ray tube, impinge upon the phosphor screen 7. The electron beams 5 are deflected in either vertical and horizontal directions by the deflection yokes 13. Furthermore, trajectory of the electron beams 5 are corrected by magnet to impinge upon a desired location on the phosphor screen 7. With the magnet, color purity is improved.
Recently, a color cathode ray tube is getting larger in size and becomes to have wide angle. As color cathode ray tube is getting larger in size, the explosion of the panel or the funnel by external shock increases accordingly. Therefore, the structure of a color cathode ray tube becomes important.
In this regard, a reinforcing band 15 is attached to the sidewall portion of the panel 2 to reinforce strength of the panel or the funnel. Also, corners of the panel 2 are designed to have a predetermined curvature to prevent the cathode ray tube from being exploded by external shock.
Accordingly, In the conventional color cathode ray tube, the weight and cost of the panel account for 50 percent of overall weight and cost of the color cathode ray tube.
For example, in the conventional color cathode ray tube having an effective diagonal diameter of 68 cm and a vertical and horizontal ratio of 16:9 for an effective screen, the weight and cost of the panel account for 40 and 60 percent of overall weight and cost of the color cathode ray tube, respectively.